In many well applications, tractors are employed to facilitate movement of equipment along a wellbore. A tractor may be connected to the well equipment in a manner such that the tractor acts against a surrounding wellbore wall to apply a force which moves the equipment in a desired direction along the wellbore. Many tractors are designed with driving wheels which rotate while gripping the surrounding wellbore wall to move the tractor. Such tractors may be employed in a variety of downhole environments, including oil well environments which have high concentrations of paraffin or wax content, large amounts of built up scale, or other types of debris. The debris found in wellbore environments tends to clog teeth on the driving wheels which reduces the gripping capability of the driving wheels. In some of these applications, the casing or other tubing against which the tractor acts to move the equipment may comprise plastic coatings that can be damaged by the tractor.